I'm arriving in Paris on a Sunday morning for a 5 day stay. I am most likely buying a 4 day museum pass, but I also know that most museums are closed on Monday. So... should I "start" my pass on Sunday, my arrival day and miss out on Thursday, or should I wait until Monday to "start" and take advantage of having all day Thursday?
Many museums in Paris are open on Monday, including the Louvre, Cluny and Orangerie. The Museum Pass can also be used for Notre Dame and Saint Chapelle and other sights which are open daily.
Rhonda is right: there are any number of attractions open on Monday which the pass may be used for so I would 'start' it Monday morning.
If you have bought Rick Steves' Paris book check out P74. That page lets you know what is open early and late and what days those sites are closed. The Louvre is closed on Tuesday for instance. We are leaving Paris on Wednesday and this page has been invaluable planning our days. Best of luck no matter what day you decide to start your pass. My wife and I bought a six day pass and have saved almost 60 euro!
Use Sunday to walk around and enjoy seeing Paris. Also, if you're arriving from overseas, the first day is good to stay outside to help adjust to the time zone change.
We asked some friends for some of their recommendations for which museums to tour since the husband is a history teacher. We enjoyed stopping in several museums, and with the pass, we didn't feel like to needed to stay long at one location if it wasn't our favorite. (We added the Cluny Museum & Napoleon's Tomb from his recommendations)
We just returned from Paris and bought the Museum Pass. They don't fill out the pass with a start date, you do. So, just put it in your pocket and fill it out before the first time you use it...
Secondly, both The Louvre ticket checkers and The d'Orsay barely even glanced at the pass. I'm not sure it even mattered what dates I had written on it even mattered.
In addition to the places listed above, the Museum Pass is also good for the Arc de Triomphe. I was so entranced with the view from there that I climbed up twice - once by day and once by night. I might have done this if I were paying separately, but because it was included in the pass, I was sure to do so.
Thanks for the advice! I'm convinced to start it on the Monday of my visit!
On Sunday you might also want to stop in at Musee Carnavalet for an overview of some Parisian history. That one is free all the time, and while parts are undergoing maintenance, others will be open.